Mounting means for the lower reciprocable bolt blade of a cutter head for a dry shaver



Sept. 3, 1968 E. LISKA 3,399,454

MOUNTING MEANS FOR THE LOWER RECIPROCABLE BOLT BLADE OF A CUTTER HEAD FOR A DRY SHAVER 3 Sheets-Sheet 1 Filed Dec. 6, 1965 Sept. 3, 1968 E s 3,399,454

MOUNTING MEANS FOR THE LOWER RECIPROCABLE BOLT BLADE OF A CUTTER HEAD FOR A DRY SHAVER 3 Sheets-Sheet 2 Filed Dec. 6, 196:

#76. 5 9 FIG. 6

Sept. 3, 1968 E. LISKA MOUNTING MEANS FOR THE LOWER RECIPROCABLE BOLT BLADE OF A CUTTER HEAD FOR A DRY SHAVER 3 Sheets-Sheet 5" Filed Dec. 6, 1965 5i EEEEEEEE iE- QE United States Patent 3,399,454 MOUNTING MEANS FOR THE LOWER RECIPRO- CABLE BOLT BLADE OF A CUTTER HEAD FOR A DRY SHAVER Erich Liska, Hitzendorf, Styria, Austria, assignor to Payer- Lux Eduard Payer, Graz, Styria, Austria, 2 company Filed Dec. 6, 1965, Ser. No. 511,814 Claims priority, application Austria, Dec. 9, 1964, A 10,400/64 2 Claims. (Cl. 3043.92)

ABSTRACT OF THE DISCLOSURE A cutter head for dry shavers in which a lower blade re'ciprocable in a predetermined direction in contact with a perforated stationary blade has secured thereto the first end of aresilient element with the second end of the resilient element bearing on a blade support detachably connected to the cutter head body for providing an abutment for the second head. The resilient element is arranged for urging the lower blade against the stationary blade with the abutment being provided with a slide face and the second end of the resilient element being provided with a slide member bearing on said slide face and displaceable in a predetermined direction relative to the abutment along the blade support.

This invention relates to a cutter head for dry shavers, e.g., electric razors, which cutter head comprises a perforated stationary blade held on the cutter head body, and a reciprocable lower blade urged against the stationary blade and supported by at least one resilient element on a blade support or carrying frame detachably connected to the cutter head body.

In connection with cutter heads of this type, it is known to provide for the attachment to the lower blade of one end of the springs which constitute the resilient elements and for the attachment of the other end of these springs to the carrying frame, preferably by gripping. In shavers provided with such a cutter head, the cutter head body together with the lower blade can be removed and replaced by another cutter head. In cutter heads of the kind described, the attachment of the spring ends to the carrying frame and to the lower blade must be absolutely reliable because otherwise the Spring ends will come loose as a result of the movement of the lower blade and may then give rise to damage. Besides, the lower blade does no longer snugly contact the stationary blade when one spring end has come loose. A further disadvantage of these known designs is that the springs are liable to break under the buckling and bending stresses to which they are subjected unless the springs are of expensive, special spring material.

Another dry shaver is known in which the lower blade is directly supported by the housing for the drive motor, and four ball bearing assemblies are interposed between the lower blade and said housing. In this case, the stationary blade is stretched about the lower blade and is not secured in a separate cutter head body but the two longitudinal edges of this stationary blade are anchored in the housing for the drive motor. For this reason, this known shaver can be used only with a single blade assembly and no provision is made for a different assembly, such as a cutter head comprising a comb. Moreover, this design is objectionable in that the lower blade is not resiliently urged against the stationary blade.

In another known cutter head, said lower blade is supported at its ends by balls or annular rollers which roll on spring guide pins associated with coil springs mounted in guide cylinders provided in the base. This design is undesirable in that the stroke of the lower blade must necessarily be small because special stops in the form of pivot pins must be provided to avoid an angular misalignment of the spring guide pins. I

In a cutter head of the type described initially hereinbefore, the above-mentioned disadvantages are avoided according to the invention in that at least one end of the resilient element is displaceable at least in the direction of movement of the lower blade. The essential advantages of the present design are that the life of the resilient element is increased and the resistance presented to the drive systern is reduced. This enables either a reduction in driving power or an increase in cutting force.

In carrying out the invention, the displaceable end of the resilient element is suitably connected to a slide member and each slide member is desirably snported by a slide face which is preferably provided on the carrying frame.

In another preferred embodiment, the displaceable end of the resilient element is supported by revolvable elements which may be mounted in the carrying frame, with a slide member being interposed, if desired, between the displaceable end of the resilient element and the revolvable elements. In this case, the revolvable elements are desirably mounted with the aid of a retainer and this retainer embraces a portion of the carrying frame. In these preferred embodiments, one end of the resilient element is preferably firmly secured to the lower blade.

Another preferred embodiment is distinguished in that the revolvable elements are rollers, with each roller having a shaft, arranged for a displacement normal to the hearing surface of the carrying frame in a carrier firmly connected to the lower blade, and said shaft is spring-cushioned by means of a spring mounted on the lower blade.

In a cutter head of this design, any wear will be compensated for by an automatic readjustment of the rollers, and the life of the stationary blade and of the cutter head as a whole will be prolonged. In addition, flutter of the lower blade and chafing on the stationary blade will be avoided. Another advantage of this design resides in that the required coupling, the retainer for the rollers, the mounting-means for the rollers and the spring retainer are combined in a single component which consists of the carrier. This carrier may be injection-molded from plastic material so that the weight is also reduced.

The invention will be explained more fully with reference to illustrated embodiments shown on the drawing, in which FIG. 1 is a longitudinal sectional view showing a cutter head,

FIG. 2 a sectional view taken on line II-II in FIG. 1,

FIG. 3 a longitudinal sectional view showing a different embodiment of a cutter head, and

FIG. 4 a sectional view taken on line IVIV in FIG. 3,

FIGS. 5 and 6 show special designs of resilient elements,

FIG. 7 is a longitudinal sectional view showing a further cutter head illustrating the invention,

FIG. 8 a transverse sectional view taken on line VIIIVIII of FIG. 7 and showing the cutter head thereof, and

'FIG. 9 a broken-away perspective view showing a carrier for the rollers.

Each of the cutter heads shown in FIGS. 1 to 4 is provided with a perforated stationary blade 1 which is held on a cutter head body 33. A reciprocable lower blade 2 is provided under the stationary blade 1 and is supported by a blade support, preferably a carrying frame 3, which is detachably connected to the cutter head body 33. The carrying frame 3 is held by two clamping bars 4 secured by screws 5 to the cutter head body 33. The clamping bars 4 are formed with projections 6 which engage recesses 7 of the carrying frame 3. The screws 5 serve also for securing the stationary blade 1 so that the blade is preferably held only at its longitudinal edges. The stationary blade 1 is suitably formed with punched elongalte'd holes through which the screws extend and which screws are threaded into the clamping bars 4. A certain play of the stationary blade 1 may be provided for to enable a displacement thereof such as by the provision of sleeves, which are fitted on each of the screws 5. In this way, the stationary blade 1 can conform to the lower blade 2 and provide a yielding guide for the lower blade which is independent on the precision with which the drive mechanism has been installed. The stationary blade 1 may be curved approximately in accordance with a parabola, and the lower blade 2 may have semicylindrical cutting faces. The lower blade 2 may be pivotally movable and laterally displaceable and is supported on the carrying frame 3 by two resilient elements consisting of coil springs 8. One end of each coil spring 8 is secured to the lower blade 2 by a pin 9 having a shoulder and preferably of plastic material. The other end of each spring is connected by a pin 11 to a slide member 10 preferably of plastic material. The pins 9 and 11 are firmly gripped by the ends of the spring 8.

According to FIGS. 1 and 2, the slide member 10 bears on a slide face 12, which is provided on the carrying frame 3 and consists preferably of metal, particularly steel, or sintered material, such as graphite bronze. The slide face 12 is laterally limited by bulges 13 or the like formed in the carrying frame. The bulges 13 provide a travel path for enabling the slide member 10 to move along with the reciprocable lower blade in said path.

According to FIGS. 3 and 4, each slide member 10 is supported by revolvable elements in the form of rollers 14. The latter are mounted in a retainer 15 of plastic material and embraces a portion 16 of the carrying frame 3.

FIG. 5 shows a coil spring 18, the ends of which are smaller in diameter than the intermediate portion. The use of such springs has the additional advantage that in spite of the gripping of the pins 9 and 11 or the like, the ends of these springs act like articulated joints so as to reduce the stress imparted to the springs whereas the intermediate portion resists buckling due to its larger outside diameter.

FIG. 6 shows an element 19 of rubber or plastic material which serves as a resilient element and has the abovementioned advantages. The ends of this element are preferably tapered and gripped by caps 20 and 21, respectively. One of said caps constitutes a slide member. The other is rigidly secured to the lower blade 2 or to the carrying frame 3.

In the embodiment shown in FIGS. 7 to 9, parts 1 to 7 and 33 are the same in design and arrangement as in the preceding embodiments.

However, the lower blade 2 is provided with rollers 22 which bear on a bearing surface 23 of the carrying frame 3. In the embodiment shown, two rollers 22 are provided at the front and rear ends, respectively, of the lower blade 2. Each roller 22 has a shaft 24 which is guided at each end of the roller in an elongated aperture 25 which extends normal to the bearing surface 23 and is guided by a carrier 26 firmly connected to the lower blade 2.

The free ends of arms 27 of a resilient yoke 28 engage the ends of each roller shaft 24. This yoke tends to urge the roller 22 away from the lower blade 2. The arms 27 of the yoke 28 are connected by a cross-bar portion 30 held in a recess 31 of the carrier 26 and extend around projections or pins 29, which protrude laterally from the carrier 26.

In order to prevent lateral movements of the rollers 22 and of the'lower blade 2, the bearing surface 23 may be provided with a shallow guide groove 32, the side walls of which are engaged by the ends of the rollers 22. As the rollers 22 are mounted on the blade side in such a manner that they are nondisplaceable transversely to the direction of movement of the lower blade 2, the blade is not capable of performing a transverse movement.

The carrier 26, which is firmly connected to the lower blade 2, consists preferably of a single injection-molded piece of plastic material and is provided with a coupling portion.

The operation of theinvention is as follows:

In each embodiment, the lower blade 2 is reciprocable in a predetermined direction in contact with the stationary blade 1 and two resilient elements 8 and 28 respectively, function for urging the blade 2 against the blade 1. Each of the resilient elements is secured to the lower blade and is provided with an end displaceable relative to the blade support which is a carrying frame. In FIGURES 1 and 2, each element 8 is provided with a slide member 10 sliding on the blade support 3 while in FIGURES 3 and 4 revolvable elements 22 roll between the slide member and the blade support. In FIGURES 7-9 the ends of the resilient elements 28 rest on the shafts 24 of the rollers 22 which roll on the carrying frame 3.

This invention is not to be confined to any strict conformity to the showings in the drawings but changes and modifications may be made therein so long as such changes or modifications mark no material departure from the spirit and scope of the appended claims.

What I claim is: p

1. A cutter head for dry shavers comprises a cutter head body, a perforated stationary blade held on said cutter head body, a blade support detachably connected to said cutter head body, a lower blade reciprocable in a predetermined direction in contact with said stationary blade, and at least one resilient element having first and second opposite ends, said first end being secured to said lower blade, said second end of the resilient element secured to a slide member, said support having a slide face on which said slide member bears, said slide member being slidable along with the reciprocable lower blade and said resilient element being arranged for urging said lower blade against said stationary blade.

2. The cutter head as set forth in claim 1, in which said blade support is formed with bulges, which limit said slide face in a direction which is at right angles to said predetermined direction.

References Cited UNITED STATES PATENTS 2,141,582 12/1938 Wimberger 30-34.1 2,236,760 4/1941 Muros et al 30-4392 2,273,524 2/1942 Jensen et al 30-4392 2,296,134 9/1942 Wright 30-4392 2,472,853 6/1949 Lorenz 3043.6 2,702,938 3/1955 Jepson 30-4392 2,819,518 1/1958 Lussier 30-34.1 2,859,513 11/1958 Bylund 30-4392 2,867,737 1/ 1959 Bylund 30-4392 X 3,074,161 1/1963 Liska 30-4392 3,169,313 2/1965 King 30-4392 FOREIGN PATENTS 524,412 8/1940 Great Britain.

451,739 9/1949 Italy. 378,572 6/ 1965 Switzerland.

MYRON c. KRUSE, Primary Examiner. I 

